1. Field of the Invention
This invention relates to improvements in an image stabilizing device in a camera for preventing the image blur of the camera caused by hand vibration or the like.
2. Related Background Art
In modern cameras, important operations for photographing such as exposure determination and focusing are all automatized and therefore, even a person unskilled in camera operation very rarely fails in photographing, but it has been difficult to automatically prevent the failure in photographing caused by camera vibration.
So, in recent years, cameras have been researched which prevent even the failure in photographing attributable to camera vibration and particularly, development and studies haven been put forward about cameras directed to the purpose of preventing the failure in photographing caused by the photographer's hand vibration. The hand vibration of a camera during photographing, if taken as an example, is a vibration of a frequency usually of 1 HZ to 12 HZ, and an attempt has been made to detect such vibration of the camera and displace a correction lens in order to correct an image blur in conformity with the detected value, thereby enabling an object free of vibration to be confirmed in a viewfinder even if a vibration is caused to the camera, and enabling a photograph free of image blur to be taken.
Theoretically speaking, the detection of the vibration of a camera can be accomplished by carrying on the camera a vibration sensor for detecting angular acceleration, angular velocity or the like, and a camera vibration detecting system for electrically or mechanically integrating the output signal of said sensor and outputting angular displacement. On the basis of this detected information, a correction optical mechanism having as correction optical means a correction lens for making the photographing optical axis eccentric or inclined is driven to thereby effect the correction (suppression) of image vibration.
Here, the outline of a camera with the image vibration correcting function using an angular acceleration meter will be described with reference to FIG. 7 of the accompanying drawings. This example is one in which an image blur resulting from a vertical camera vibration 51p and a horizontal camera vibration 51y in the directions of arrows 51 is suppressed.
In FIG. 7, the reference numeral 52 designates a lens barrel, and the reference characters 53p and 53y denote angular acceleration meters for detecting the angular acceleration of the vertical camera vibration and the angular acceleration of the horizontal camera vibration, respectively. The angular acceleration detection directions of these meters are indicated by 54p and 54y, respectively. The reference characters 55p and 55y designate integrators each constructed by the use of a conventional analog integration circuit. These integrators integrate the signals of the respective angular acceleration meters and convert them into hand vibration angular displacement. The reference numeral 56 denotes a correction optical mechanism driven in a plane perpendicular to the optical axis in the directions 51p and 51y by said hand vibration angular displacement output (the reference characters 57p and 57y designate the driving portions thereof, and the reference characters 58p and 58y denote correction optical position detecting sensors), and the photographing optical axis is made eccentric by such movement of the correction optical mechanism, whereby there can be obtained the image vibration correcting effect in the image plane 59.
What has been described above refers to a case where image blur correction is being effected, but when image blur correction is not being effected, it is necessary to electrically or mechanically fix (lock) the correction optical mechanism 56. That is, considering the time when the camera is carried, if the correction optical mechanism 56 is not locked, a force which will restrain the movement in a plane perpendicular to the optical axis will hardly act on the correction optical mechanism 56 and therefore, the correction optical mechanism 56 will be inadvertently oscillated by the vibration of the camera when carried, and this will lead to inconveniences such as the creation of sound by the collision of the correction optical mechanism with the other surrounding members and the damage or functional destruction by the shock.
Heretofore, the locking of the correction optical mechanism 56 when image blur correction is not effected for a long time has rarely been electrically effected, that is, from the viewpoint of the saving of electric power, the correction optical mechanism has rarely been driven by an applied predetermined signal so as to assume a predetermined position, and the locking has chiefly been mechanically effected. With regard to this, Japanese Patent Publication No. 57-37852 proposes to mechanically lock and unlock a correction optical mechanism oscillated in a telescope or binoculars, and Japanese Laid-Open Patent Application No. 61-296862 proposes to mechanically lock and unlock a correction optical mechanism pivoted in a video camera.
However, both of these enable the correction optical mechanism to be locked and unlocked by operating an extraneous operating member for exclusive use. Generally, in a camera, the photographer's desire to obtain the image blur correcting effect, i.e., the necessity of an image blur corrected state with the correction optical mechanism unlocked, is within the range of a series of operations during the first stroke of a shutter release button as the photographing preparation operation in which the photographer looks into the viewfinder to confirm the object, and during the second stroke of the shutter release button as the photographing operation.
However, in the above-described examples of the prior art, the locking and unlocking of the correction optical mechanism are effected by the operation of the extraneous operating member for exclusive use therefor, and this has led to the disadvantage that the photographer is compelled to perform the cumbersome operations of locking and unlocking the correction optical mechanism discretely from the photographing preparation operation and the photographing operation.
Further, as already described, when the photographer forgets to lock the correction optical mechanism, the correction optical mechanism results in the inconvenience of being mechanically damaged by the shock of inadvertent vibration as when the camera is carried.